The present invention resides in a micro-mechanical actuator for generating forces in the range of several mN to about 100 mN and in the size range of some 100 .mu.m with a piston movable in a passage to which fluid under pressure can be supplied at one side of the piston which has at the other side a piston rod for the transmission of the force generated by the piston.
Micro-mechanical actuators are used for various purposes. However, the forces that can be generated by these actuators are still very small. The actuators known so far can be used therefore only for applications where small forces of below the mN range are sufficient. Such an actuator is known for example from Sniegowski, J. J.: "A MICRO ACTUATION MECHANISM BASED ON LIQUID VAPOR SURFACE TENSION", 7.sup.th Int. Conf. On Solid State Sensors and Actuators, Yokohama, 1993. The actuator described therein includes a piston with piston rod which is moved by a vapor bubble in a housing of larger size. The piston is sealed in the housing by the surface tension of the vapor bubble wall. The piston itself is guided and supported by two leaf springs attached to the sides of the piston rod. Since the actuator is manufactured in conventional silicon technology, it does not have any structures with a high aspect ratio. This leads necessarily to small cylinder dimensions and consequently, because of the geometric dimensions and the limitations provided by the surface tension of the vapor bubble, to only small achievable actuator forces.
It is therefore the object of the present invention to provide a micro-mechanical actuator with which substantially greater forces can be achieved than is possible with micromechanical actuators known so far.